Clock consistency checks am: 1f32bef75b

am: d6b0ff208e

Change-Id: Ie9751ec03281cf98c0c87c29fc4a755d2b6fe80c

libwvdrmengine/cdm/core/include/policy_engine.h

@@ -160,6 +160,9 @@ class PolicyEngine {
   // expiry time changes.
   void NotifyExpirationUpdate(int64_t current_time);
 
+  // Guard against clock rollbacks
+  int64_t GetCurrentTime();
+
   // set_clock() is for testing only. It alters ownership of the
   // passed-in pointer.
   void set_clock(Clock* clock);
@@ -191,6 +194,9 @@ class PolicyEngine {
   // calculate the time where renewal retries should occur.
   int64_t next_renewal_time_;
 
+  // to assist in clock rollback checks
+  int64_t last_recorded_current_time_;
+
   // Used to dispatch CDM events.
   CdmSessionId session_id_;
   WvCdmEventListener* event_listener_;

libwvdrmengine/cdm/core/src/policy_engine.cpp

@@ -16,6 +16,8 @@ using video_widevine::License;
 
 namespace {
 
+const int kCdmPolicyTimerDurationSeconds = 1;
+const int kClockSkewDelta = 5;  // seconds
 const int64_t kHdcpCheckInterval = 10;
 
 }  // namespace
@@ -34,6 +36,7 @@ PolicyEngine::PolicyEngine(CdmSessionId session_id,
       last_expiry_time_set_(false),
       was_expired_on_load_(false),
       next_renewal_time_(0),
+      last_recorded_current_time_(0),
       session_id_(session_id),
       event_listener_(event_listener),
       license_keys_(new LicenseKeys),
@@ -84,7 +87,8 @@ void PolicyEngine::CheckDevice(int64_t current_time) {
 }
 
 void PolicyEngine::OnTimerEvent() {
-  int64_t current_time = clock_->GetCurrentTime();
+  last_recorded_current_time_ += kCdmPolicyTimerDurationSeconds;
+  int64_t current_time = GetCurrentTime();
 
   // If we have passed the grace period, the expiration will update.
   if (grace_period_end_time_ == 0 && HasPlaybackStarted(current_time)) {
@@ -191,7 +195,7 @@ void PolicyEngine::UpdateLicense(const License& license) {
   license_start_time_ = license.license_start_time();
   next_renewal_time_ = license_start_time_ + policy_.renewal_delay_seconds();
 
-  int64_t current_time = clock_->GetCurrentTime();
+  int64_t current_time = GetCurrentTime();
   if (!policy_.can_play() ||
       HasLicenseOrPlaybackDurationExpired(current_time)) {
     license_state_ = kLicenseStateExpired;
@@ -216,7 +220,7 @@ void PolicyEngine::BeginDecryption() {
       case kLicenseStateCanPlay:
       case kLicenseStateNeedRenewal:
       case kLicenseStateWaitingLicenseUpdate:
-        playback_start_time_ = clock_->GetCurrentTime();
+        playback_start_time_ = GetCurrentTime();
         last_playback_time_ = playback_start_time_;
         if (policy_.play_start_grace_period_seconds() == 0)
           grace_period_end_time_ = playback_start_time_;
@@ -236,7 +240,7 @@ void PolicyEngine::BeginDecryption() {
 }
 
 void PolicyEngine::DecryptionEvent() {
-  last_playback_time_ = clock_->GetCurrentTime();
+  last_playback_time_ = GetCurrentTime();
 }
 
 void PolicyEngine::NotifyResolution(uint32_t width, uint32_t height) {
@@ -250,7 +254,7 @@ void PolicyEngine::NotifySessionExpiration() {
 
 CdmResponseType PolicyEngine::Query(CdmQueryMap* query_response) {
   std::stringstream ss;
-  int64_t current_time = clock_->GetCurrentTime();
+  int64_t current_time = GetCurrentTime();
 
   if (license_state_ == kLicenseStateInitial) {
     query_response->clear();
@@ -291,7 +295,7 @@ CdmResponseType PolicyEngine::QueryKeyAllowedUsage(
 bool PolicyEngine::GetSecondsSinceStarted(int64_t* seconds_since_started) {
   if (playback_start_time_ == 0) return false;
 
-  *seconds_since_started = clock_->GetCurrentTime() - playback_start_time_;
+  *seconds_since_started = GetCurrentTime() - playback_start_time_;
   return (*seconds_since_started >= 0) ? true : false;
 }
 
@@ -299,12 +303,12 @@ bool PolicyEngine::GetSecondsSinceLastPlayed(
     int64_t* seconds_since_last_played) {
   if (last_playback_time_ == 0) return false;
 
-  *seconds_since_last_played = clock_->GetCurrentTime() - last_playback_time_;
+  *seconds_since_last_played = GetCurrentTime() - last_playback_time_;
   return (*seconds_since_last_played >= 0) ? true : false;
 }
 
 int64_t PolicyEngine::GetLicenseOrPlaybackDurationRemaining() {
-  const int64_t current_time = clock_->GetCurrentTime();
+  const int64_t current_time = GetCurrentTime();
   const int64_t expiry_time =
       GetExpiryTime(current_time,
                     /* ignore_soft_enforce_playback_duration */ false);
@@ -328,7 +332,7 @@ void PolicyEngine::RestorePlaybackTimes(int64_t playback_start_time,
     playback_start_time_ = grace_period_end_time;
   }
 
-  const int64_t current_time = clock_->GetCurrentTime();
+  const int64_t current_time = GetCurrentTime();
   const int64_t expiry_time =
       GetExpiryTime(current_time,
                     /* ignore_soft_enforce_playback_duration */ true);
@@ -466,6 +470,15 @@ void PolicyEngine::NotifyExpirationUpdate(int64_t current_time) {
   last_expiry_time_set_ = true;
 }
 
+int64_t PolicyEngine::GetCurrentTime() {
+  int64_t current_time = clock_->GetCurrentTime();
+  if (current_time + kClockSkewDelta < last_recorded_current_time_)
+    current_time = last_recorded_current_time_;
+  else
+    last_recorded_current_time_ = current_time;
+  return current_time;
+}
+
 void PolicyEngine::set_clock(Clock* clock) { clock_.reset(clock); }
 
 }  // namespace wvcdm